Adobe AFTER EFFECTS 5.5 Help Manual page 152

Adobe After Effects Help
Using Help | Contents
To use the motion path as a replacement for an existing mask, select the mask you want
•
to replace.
6 In the Timeline, expand the Mask property for the mask you want to create or replace
and select the Mask Shape value name.
7 Choose Edit > Paste.
Drawing a Bezier mask with the pen tool
Using the pen tools, you can create a Bezier mask of any shape, including straight lines at
any angle or smooth flowing curves. The pen tools provide the most precise control over
straight lines and curves.
You can easily adjust the shape of the path by dragging the mask's control points or the
direction lines associated with a control point. You can also quickly add points to or delete
points from a segment, or change a control point from one type to another. For infor-
mation on changing control points, see the related procedure in "Changing the shape of a
mask" on page 155.
Drawing straight lines with the pen tool
With the pen tool, draw straight lines by clicking the pen tool to create control points.
Each time you click the tool in a new location, After Effects draws a straight path segment
from the previous point to the new point. To close the path, position the cursor directly
over the first control point and, when you see a closed circle icon ( ) next to the cursor,
click.
Drawing curves with the pen tool
Create a curved mask by dragging the pen tool in the direction you want the curve to go.
As with straight segments, control points mark a change in direction, but instead of
creating a corner, control points on curves create smooth changes in direction. On curved
segments, each selected control point displays one or two direction lines, ending in
direction handles. The shape of a curved segment depends on the direction line at either
end of the segment. As a path exits one control point, that point's direction line shapes the
curve. As the path approaches the next control point, its shape is less influenced by the
previous point and more influenced by the direction line at the next control point. Moving
these elements reshapes the curves in a path.
The direction lines always touch the curve at the control points. The angle and length of a
direction line determine the shape of the curve as it exits that control point.
Continuous curved paths—that is, paths along a continuous wave shape—are connected
by control points called smooth points. Noncontinuous curved paths are connected by
corner points. You can change a control point to either a smooth or corner point as you
draw.
When you move a direction line on a smooth point, the curves on both sides of the point
adjust simultaneously. By contrast, when you move a direction line on a corner point, only
the curve on the same side of the point as the direction line is adjusted. Complete the
shape by clicking the first control point or by double-clicking the last point.
To change a control point:
Do one of the following:
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Working with Masks and Transparency
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